Sildenafil

Sildenafil helps men with erectile dysfunction get and maintain an erection for sexual intercourse. It usually starts to work within 30-60 minutes.

Sildenafil Overview

Updated: April 11, 2016

Sildenafil is a prescription medication used to treat erectile dysfunction (ED). Sildenafil is also used to treat adults with pulmonary arterial hypertension (PAH).

Sildenafil belongs to a group of drugs called PDE inhibitors. Sildenafil treats ED by increasing blood flow to the penis during sexual stimulation, which leads to an erection. Sildenafil treats PAH by relaxing the blood vessels in the lungs to allow blood to flow easily.

This medication comes in tablet form and is taken one hour before sexual activity if treating for ED. It is taken 3 times a day, 4-6 hours apart, if treating for PAH.

This medication also comes as an oral suspension (liquid) and in an injectable form to be given directly into a vein (IV) by a healthcare professional.

Common side effects include headache, facial flushing, and upset stomach.

Side Effects of Sildenafil

Less common side effects that may occur are temporary changes in color vision (such as trouble telling the difference between blue and green objects or having a blue color tinge to them), eyes being more sensitive to light, or blurred vision.

In rare instances, men taking PDE5 inhibitors reported a sudden decrease or loss of vision in one or both eyes. It is not possible to determine whether these events are related directly to these medicines, to other factors such as high blood pressure or diabetes, or to a combination of these. If you experience sudden decrease or loss of vision, stop taking PDE5 inhibitors, including sildenafil, and call a doctor right away.

In rare instances, men have reported an erection that lasts many hours. You should call a doctor immediately if you ever have an erection that lasts more than 4 hours. If not treated right away, permanent damage to your penis could occur.

Sudden loss or decrease in hearing, sometimes with ringing in the ears and dizziness, has been rarely reported in people taking PDE5 inhibitors, including sildenafil. It is not possible to determine whether these events are related directly to the PDE5 inhibitors, to other diseases or medications, to other factors, or to a combination of factors. If you experience these symptoms, stop taking sildenafil and contact a doctor right away.

Heart attack, stroke, irregular heart beats, and death have been reported rarely in men taking sildenafil. Most, but not all, of these men had heart problems before taking this medicine. It is not possible to determine whether these events were directly related to sildenafil.

Sildenafil may cause other side effects besides those listed. If you want more information or develop any side effects or symptoms you are concerned about, talk to your doctor or pharmacist.

Sildenafil Interactions

Tell your doctor about all the medicines you take including prescription and non-prescription medicines, vitamins, and herbal supplements. Especially tell your doctor if you take any of the following:

medicines called alpha blockers. These include Hytrin (terazosin HCl), Flomax (tamsulosin HCl), Cardura (doxazosin mesylate), Minipress (prazosin HCl) or Uroxatral (alfuzosin HCl). Alpha blockers are sometimes prescribed for prostate problems or high blood pressure. If sildenafil is taken with certain alpha blockers, your blood pressure could suddenly drop and you could get dizzy or faint.

Do not take sildenafil if you take any medicines called “nitrates.” Nitrates are commonly used to treat angina. Angina is a symptom of heart disease and can cause pain in your chest, jaw, or down your arm.

Medicines called nitrates include nitroglycerin that is found in tablets, sprays, ointments, pastes, or patches. Nitrates can also be found in other medicines such as isosorbide dinitrate or isosorbide mononitrate. Some recreational drugs called “poppers” also contain nitrates, such as amyl nitrite and butyl nitrite.

Ask your healthcare provider or pharmacist if you are not sure if any of your medicines are nitrates.

This is not a complete list of sildenafil drug interactions. Ask your doctor or pharmacist for more information.

Sildenafil Precautions

There is potential risk of sexual activity in patients with cardiovascular risk factors. If you experience symptoms (chest pain, dizziness, nausea) upon initiation of sexual activity, it is advised to refrain from further sexual activity and discuss the episode with your doctor.

Sildenafil can cause your blood pressure to drop suddenly to an unsafe level if it is taken with certain other medicines. You could get dizzy, faint, or have a heart attack or stroke.

Tell all of your healthcare providers that you take sildenafil. If you need emergency medical care for a heart problem, it will be important for your healthcare provider to know when you last took sildenafil.

Seek immediate medical attention if sudden loss of vision occurs, which could be a sign of non-arteritic ischemic optic neuropathy (NAION).

take any medicines called “nitrates”. See "Drug Interactions" section.

use recreational drugs called “poppers” like amyl nitrite and butyl nitrite

are allergic to sildenafil or any of its ingredients. Symptoms of an allergic reaction may include:

rash

hives

swelling of the lips, tongue, or throat

difficulty breathing or swallowing

Call your healthcare provider or get help right away if you have any of the symptoms of an allergic reaction listed above.

Only your doctor can decide if sildenafil is right for you. Sildenafil can cause mild, temporary lowering of your blood pressure. You will need to have a thorough medical exam to diagnose your erectile dysfunction and to find out if you can safely take sildenafil alone or with your other medicines.

Sildenafil and Pregnancy

The FDA categorizes medications based on safety for use during pregnancy. Five categories - A, B, C, D, and X, are used to classify the possible risks to an unborn baby when a medication is taken during pregnancy.

Sildenafil Dosage

TABLETS: For most patients, the recommended dose is 50 mg taken, as needed, approximately 1 hour before sexual activity. However, sildenafil may be taken anywhere from 4 hours to 0.5 hour before sexual activity. Your doctor may increase the dose to a maximum recommended dose of 100 mg or decreased it to 25 mg. Sildenafil is to be taken only once per day.

For the treatment of pulmonary arterial hypertension (PAH):

TABLETS and ORAL SOLUTION: The recommended dose of sildenafil is 20 mg three times a day. Take sildenafil doses 4–6 hours apart. Doses higher than 20 mg three times a day is not recommended.

INJECTABLE: The recommended dose is 10 mg (12.5 mL) given as an injection into the vein (IV) three times a day.

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